Method and apparatus for releasably attaching a polishing pad to a chemical-mechanical planarization machine

ABSTRACT

A method and apparatus for releasably attaching a planarizing medium, such as a polishing pad, to the platen of a chemical-mechanical planarization machine. In one embodiment, the apparatus can include several apertures in the upper surface of the platen that are coupled to a vacuum source. When a vacuum is drawn through the apertures in the platen, the polishing pad is drawn tightly against the platen and may therefore be less likely to wrinkle when a semiconductor substrate is engaged with the polishing pad during planarization. When the vacuum is released, the polishing pad can be easily separated from the platen. The apparatus can further include a liquid trap to separate liquid from the fluid drawn by the vacuum source through the apertures, and can also include a releasable stop to prevent the polishing pad from separating from the platen should the vacuum source be deactivated while the platen is in motion. In another embodiment, a signal can be applied to the platen to draw the polishing pad toward the platen via electrostatic or electromagnetic forces. In still another embodiment, the polishing pad can be attached to a pad support and conditioned on a separate jig.

TECHNICAL FIELD

[0001] The present invention relates to methods and devices forreleasably attaching polishing pads to the platens ofchemical-mechanical planarization machines.

BACKGROUND OF THE INVENTION

[0002] Chemical-mechanical planarization (“CMP”) processes removematerial from the surface of a semiconductor wafer in the production ofintegrated circuits. FIG. 1 schematically illustrates a CMP machine 10with a platen 20, a wafer carrier 60, a polishing pad 40, and aplanarizing liquid 41 on the polishing pad 40. The polishing pad 40 maybe a conventional polishing pad made from a continuous phase matrixmaterial (e.g., polyurethane), or it may be a fixed abrasive polishingpad made from abrasive particles fixedly dispersed in a suspensionmedium. The planarizing liquid 41 may be a conventional CMP slurry withabrasive particles and chemicals that etch and/or oxidize the wafer, orthe planarizing liquid 41 may be a planarizing solution without abrasiveparticles that contains only chemicals to etch and/or oxidize thesurface of the wafer. In most CMP applications, conventional CMPslurries are used on conventional polishing pads, and planarizingsolutions without abrasive particles are used on fixed abrasivepolishing pads.

[0003] The CMP machine 10 also has an underpad 25 attached to an uppersurface 30 of the platen 20 and the lower surface of the polishing pad40. In one type of CMP machine, a drive assembly 50 rotates the platen20 as indicated by arrow A. In another type of CMP machine, the driveassembly reciprocates the platen back and forth as indicated by arrow B.Since the polishing pad 40 is attached to the underpad 25, the polishingpad 40 moves with the platen 20.

[0004] The wafer carrier 60 has a lower surface 63 to which a wafer 12may be attached, or the wafer 12 may be attached to a resilient pad 64positioned between the wafer 12 and the lower surface 63. The wafercarrier 60 may be a weighted, free-floating wafer carrier, or anactuator assembly 61 may be attached to the wafer carrier to impartaxial and/or rotational motion (indicated by arrows C and D,respectively).

[0005] To planarize the wafer 12 with the CMP machine 10, the wafercarrier 60 presses the wafer 12 face-downward against the polishing pad40. While the face of the wafer 12 presses against the polishing pad 40,at least one of the platen 20 or the wafer carrier 60 moves relative tothe other to move the wafer 12 across the planarizing surface 42. As theface of the wafer 12 moves across the planarizing surface 42, thepolishing pad 40 and the planarizing liquid 41 continually removematerial from the face of the wafer 12.

[0006] CMP processes must consistently and accurately produce a uniform,planar surface on the wafer to enable precise circuit and devicepatterns to be formed with photolithography techniques. As the densityof integrated circuits increases, it is often necessary to accuratelyfocus the critical dimensions of the photo-patterns to within atolerance of approximately 0.1 μm. Focusing photo-patterns of such smalltolerances, however, is difficult when the planarized surface of thewafer is not uniformly planar. Thus, CMP processes must create a highlyuniform, planar surface.

[0007] One problem with conventional CMP processing techniques is thatthe planarized surface of the wafer may not be sufficiently uniform dueto nonuniformities that may develop in the planarizing surface of thepolishing pad during planarization. One conventional approach toaddressing this problem is to firmly attach the polishing pad to theplaten to decrease the likelihood that the polishing pad will warp orwrinkle as the wafer carrier and substrate move across the planarizingsurface. For example, in one conventional approach, the polishing padmay be attached to the platen with a high-strength adhesive. Onedrawback with this approach is that the planarizing surface of thepolishing pad typically wears out during normal use and the polishingpad must therefore be replaced. It may be difficult and time consumingto remove the polishing pad and the high-strength adhesive from theplaten, rendering the CMP machine inoperable for extended periods oftime.

[0008] One conventional approach to addressing the foregoing problem isto manufacture a sheet of polishing pad material and stretch it acrossthe platen from one side to the other. As the polishing pad wears, it isincrementally moved across the platen in the manner of a conveyor beltto present an unworn planarizing surface to the wafer. Such a device ismanufactured by Obsidian, Inc. of Fremont, Calif. One problem with thisapproach is that the tension in the sheet may not be sufficient to keepit flat against the platen. Accordingly, the sheet may tend to wrinkleor fold upon itself under the pressure exerted by the wafer carrier andthe wafer.

SUMMARY OF THE INVENTION

[0009] The present invention is directed toward a method and apparatusfor releasably attaching a planarizing medium to a chemical-mechanicalplanarization machine. The apparatus can comprise a support and a platenhaving an engaging surface with one or more vacuum apertures sized andshaped to be coupled to a vacuum source. A planarizing medium can betightly drawn against the engaging surface of the platen when the vacuumsource applies a vacuum to the vacuum apertures. The planarizing mediumcan include a polishing pad having a generally non-porous surface thatseals against the engaging surface of the platen. Alternatively, theplanarizing medium can include a porous polishing pad adhesivelyattached to a pad support. The pad support may have a generallynon-porous surface opposite the polishing pad that seals against theplaten when the vacuum source is activated. In yet another alternativeaspect of the invention, the polishing pad and the pad support can besupported, for example, in a support jig, to condition the polishingpad. In still another alternative aspect of the invention, a signal canbe applied to the platen to attract the polishing pad toward the platenvia electrostatic or electromagnetic forces.

[0010] The platen may be movable relative to the support and may includea lip to prevent the planarizing medium from separating from the platenif the vacuum source is deactivated while the platen is still in motion.The platen may also include a releasable stop to further engage theplanarizing medium. Alternatively, the platen may be replaced by a basethat is fixed relative to the support and the apparatus may furtherinclude a supply device and a take-up device that advance an elongatedplanarizing medium across the base. During planarization, the vacuumsource draws the planarizing medium against the base. When theplanarizing medium becomes worn (or for other reasons), the vacuumsource or charge source may be deactivated and the planarizing mediummay be advanced across the base to expose a different portion of theplanarizing medium to the semiconductor substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a partial cross-sectional elevation view of achemical-mechanical planarization machine in accordance with the priorart FIG. 2 is a partial cross-sectional elevation view of an apparatushaving a platen with vacuum apertures in accordance with an embodimentof the present invention.

[0012]FIG. 3 is a top plan view of the platen shown in FIG. 2.

[0013]FIG. 4 is a top plan view of a platen having vacuum apertures inaccordance with another embodiment of the invention.

[0014]FIG. 5A is a partial cross-sectional elevation view of a platenhaving a locking device in accordance with yet another embodiment of theinvention.

[0015]FIG. 5B is a partial cross-sectional elevation view of a jig usedto support a platen in accordance with another embodiment of theinvention.

[0016]FIG. 6 is a partial cross-sectional elevation view of a platenhaving a locking device in accordance with still another embodiment ofthe invention.

[0017]FIG. 7A is a partial cross-sectional elevation view of a platenhaving a plate to attract the pad support disk in accordance with stillanother embodiment of the invention.

[0018]FIG. 7B is a partial cross-sectional elevation view of a platenhaving a plate to attract the polishing pad in accordance with yetanother embodiment of the invention.

[0019]FIG. 8 is a partial cross-sectional elevation view of an apparatushaving a supply device and a take-up device in accordance with stillanother embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention is directed toward methods and devices forattaching a polishing pad to a platen of a chemical-mechanicalplanarization machine. The device may include a vacuum system thatreleasably attaches the polishing pad to the platen such that thepolishing pad may be easily removed and/or replaced, or may beincrementally advanced over the platen. Many specific details of certainembodiments of the invention are set forth in the following descriptionand in FIGS. 2-7 to provide a thorough understanding of suchembodiments. One skilled in the art, however, will understand that thepresent invention may have additional embodiments and that they may bepracticed without several of the details described in the followingdescription.

[0021]FIG. 2 illustrates a CMP apparatus 110 having a platen 120 and aplanarizing medium 148. Ithe embodiment shown in FIG. 2, the planarizingmedium 148 includes polishing pad 140 releasably attached to the platen120, and in other embodiments, the planarizing medium 148 may includeother components, as is discussed in greater detail below with referenceto FIG. 5. The platen 120 may be movable relative to a support structure180 by means of a platen drive assembly 150 that may impart rotationalmotion (indicated by arrow A) and/or translational motion (indicated byarrow B) to the platen 120. As was discussed above, the CMP apparatus110 may also include a carrier assembly 160 having a resilient pad 164that presses a semiconductor substrate 112 against a planarizing surface142 of the polishing pad 140. A carrier drive assembly 161 may becoupled to the carrier assembly 160 to move the carrier assembly axially(indicated by arrow C) and/or rotationally (indicated by arrow D)relative to the platen 120.

[0022] The platen 120 has an upper surface 130 adjacent the polishingpad 140. The upper surface 130 includes a plurality of vacuum apertures122 that are in fluid communication with a vacuum passageway 123. Thevacuum passageway 123 is coupled to a vacuum source 170, as will bediscussed in greater detail below, such that when the vacuum source 170is activated, it draws a vacuum through the vacuum apertures 122 anddraws the polishing pad 140 tightly against the upper surface 130 of theplaten 120.

[0023]FIG. 3 is a top plan view of the platen 120 and the polishing pad140 shown in FIG. 2. Referring to FIGS. 2 and 3, the vacuum apertures122 of the platen 120 may have a circular cross-sectional shape at theplaten upper surface 130 and may have other shapes in other embodiments,as will be discussed below with reference to FIG. 4. The platen 120 mayhave twelve vacuum apertures 122, as shown in FIGS. 2 and 3, and mayhave a greater or lesser number of vacuum apertures 122 in otherembodiments, so long as the force exerted by the vacuum source 170 (FIG.2) through the vacuum apertures 122 is sufficient to secure thepolishing pad 140 to the platen 120. In one embodiment, the vacuumsource 170 may generate a vacuum pressure of 10 lb/in² (6.9×10⁴ N/m²)below atmospheric pressure, measured at the vacuum apertures 122. Inother embodiments, the vacuum source 170 may generate other pressuressufficient to secure the polishing pad 140 to the platen 120, dependingon the characteristics of the polishing pad 140 and the size, shape, andnumber of the vacuum apertures 122.

[0024] The vacuum apertures 122 extend downwardly through the platenupper surface 130 to the vacuum passageway 123 below. In the embodimentshown in FIGS. 2 and 3, the vacuum passageway 123 may have a pluralityof radially extending arms 131 that meet near the center of the platen120. In other embodiments, the vacuum passageway 123 may have otherconfigurations that provide fluid communication between the vacuumapertures 122 and the vacuum source 170.

[0025] As shown in FIG. 2, each arm 131 of the vacuum passageway 123 mayhave a liquid trap 124 to separate liquid from the fluid stream thatpasses through the vacuum passageway 123 when the vacuum source 170 isactivated. The fluid stream may include air or other gases adjacent theplanarizing surface 142, as well as liquids, such as a planarizingliquid 141. In one embodiment, the liquid trap 124 may include avertical bend in each arm 131 and a vertical collection tube 132 at thelow point of each bend. Liquid drawn into the vacuum passageway 123 willtend to settle in the collection tubes 132 under the force of gravity. Avalve 125 may be positioned at the base of each of the collection tubes132 to periodically drain the liquid collected in the liquid trap 124.

[0026] In other embodiments, other means may be used to separate liquidfrom the fluid drawn through the vacuum passageway 123. For example, theliquid trap 124 may be separate from the platen 120, as discussed ingreater detail below with reference to FIG. 7, and/or the liquid trapmay be integral with the vacuum source 170. In another embodiment (notshown), where the angular velocity of the platen 120 is relatively high,the liquid trap may be positioned toward the outer edge of the platen120 and may take advantage of centrifugal forces to separate liquid fromthe fluid stream passing through the vacuum passageway 123. An advantageof the gravity-driven liquid trap 124 shown in FIG. 2 may be that itwill continue to collect liquid when the platen 120 has stoppedrotating.

[0027] A rotary drive 151 may be coupled to the platen 120 with a rotarydrive shaft 153 to rotate the platen 120, as indicated by arrow A. Therotary drive shaft 153 may include a central passage 155 that extendsfrom the vacuum passageway 123 to a non-rotating conduit 128. Theconduit 128 is in turn coupled to the vacuum source 170. A rotating seal126 may be coupled between the conduit 128 and the rotating drive shaft153 to provide a gas-tight seal between the conduit and the drive shaftand maintain vacuum pressures in the vacuum passage 123 when the platen120 rotates relative to the vacuum source 170.

[0028] The platen 120 may also be translated and/or oscillated by alinear drive 152 coupled to the platen with a linear drive shaft 154. Inone embodiment, the linear drive shaft 154 may include telescopingsegments 154 a and 154 b. In other embodiments, splines or other meansmay be used to transmit lateral motion from the fixed linear drive 152to the platen 120. The conduit 128 may include a bellows section 133that expands and contracts as the platen 120 moves laterally relative tothe vacuum source 170. In other embodiments, other means may be used tocouple the vacuum source 170 to the translating platen 120. For example,in one such embodiment (not shown), the conduit 128 may be coiled in themanner of a telephone cord to account for relative lateral motionbetween the platen 120 and the vacuum source 170.

[0029] The platen 120 may include a lip 121 that extends upwardly fromthe platen upper surface 130 to engage a side surface 146 of thepolishing pad 140 and prevent the polishing pad from sliding off theplaten 120 if the vacuum source 170 is deactivated while the platen 120is in motion. The lip 121 may accordingly engage the entire side surface146, as shown in FIG. 2, or a portion of the side surface 146. Forexample, the lip 121 may engage less than the fill height of the sidesurface 146, or may extend around less than the entire periphery of thepolishing pad 140, so long as it engages enough of the side surface 146to prevent the polishing pad 140 from sliding laterally off the platen120. In other embodiments, other means may be used to restrict motion ofthe polishing pad 140 relative to the platen 120, as will be discussedin greater detail with reference to FIGS. 5 and 6.

[0030] In one embodiment, the polishing pad 140 may comprise a nonporousor nearly non-porous material that provides a gas-tight or nearlygas-tight seal with the platen upper surface 130 when a vacuum is drawnthrough the vacuum apertures 122. For example, the polishing pad 140 maycomprise polymers such as polyurethane, or may comprise glass or othernon-porous materials. In another embodiment, the polishing pad 140 maycomprise porous materials, as will be discussed in greater detail belowwith reference to FIG. 5.

[0031] One advantage of the CMP apparatus 110 shown in FIGS. 2-3 is thatthe polishing pad 140 may be easily removed from the platen 120 when,for example, the polishing pad is replaced due to normal wear or forother reasons. To replace the polishing pad 140, the vacuum source 170is deactivated or otherwise decoupled from the platen 120, the polishingpad 140 is lifted from the platen, and a new polishing pad is positionedin its place. The entire operation may be completed in a relativelyshort period of time. By contrast, it may take a substantially longerperiod of time to detach a conventional, adhesively bonded polishing padfrom the platen 120, remove any remaining adhesive from the platen, andadhesively bond a replacement polishing pad to the platen.

[0032] Another advantage of the CMP apparatus 110 shown in FIGS. 2-3 isthat the vacuum source 170 may be deactivated when the polishing pad 140is not in. use and may be subsequently reactivated without affecting thebonding force between the polishing pad 140 and the platen 120. Bycontrast, the adhesives that may be used in conventional installationsto bond the polishing pad 140 to the platen 120 may degrade over time,causing the bond between the polishing pad and the platen to fail.

[0033]FIG. 4 is a top plan view of a platen 220 having concentric,arcuate vacuum apertures 222. Each vacuum aperture 222 is in fluidcommunication with the arms 231 of the vacuum passageway 223, as wasdiscussed above with reference to FIG. 2. An advantage of the arcuatevacuum apertures 222 when compared with the vacuum apertures 122 shownin FIGS. 2-3 is that the arcuate vacuum apertures may have a greatertendency to prevent the polishing pad 140 from wrinkling in the radialdirection. Conversely, an advantage of the platen 120 having the vacuumapertures 122 shown in FIGS. 2-3 is that it may be simpler and lessexpensive to manufacture.

[0034]FIG. 5A is a partial cross-sectional side elevation view of aplaten 320 having a vacuum source 370 attached thereto. The vacuumsource 370 is accordingly coupled to the vacuum passageway 323 withoutthe need for intervening conduits and rotating and/or translatinggas-tight seals. In the embodiment shown in FIG. 5A, a power supply 371is attached to the platen 320 and coupled to the vacuum source 370 toprovide power to the vacuum source. The power supply 371 may include abattery, a solar panel, or other known devices that may supply power tothe vacuum source 370 during planarization without the need for externalconnections. In another embodiment (not shown), the power supply 371 maybe positioned apart from the platen 320 and may be coupled to the vacuumsource 370 with slip rings or other rotating electrical connections.

[0035] In one embodiment, the vacuum source 370 and the power supply 371may be relatively light in weight to reduce the power required by theplaten drive assembly 150 (FIG. 2) to translate and/or rotate the platen320. The platen 320 may also include a counterweight 372 positionedopposite the vacuum source 370 and the power supply 371 to balance theplaten and reduce the likelihood that the platen will vibrate when itrotates. The counterweight 372 may comprise a simple dead weight or maycomprise a functioning component of the platen 320, as is discussed ingreater detail below with reference to FIG. 6.

[0036] An advantage of the vacuum source 370 and the power supply 371shown in FIG. 5A is that they may eliminate the need for rotating and/ortranslating seals and electrical connections, as discussed above, andmay accordingly simplify the construction and maintenance of the platen320. Conversely, an advantage of the stationary vacuum source 170 shownin FIG. 2 is that it may include an existing commercially availabledevice that need not be balanced and/or selected for low weight.

[0037] As shown in FIG. 5A, the planarizing medium 348 may include apolishing pad 340 attached to a pad support disk 343. The pad supportdisk 343 may have a generally non-porous attachment surface 347 thatforms a gas-tight or nearly gas-tight seal with the platen upper surface330. In the embodiment shown in FIG. 5A, the polishing pad 340 isattached to the pad support disk 343 with an adhesive 344 positionedtherebetween. In other embodiments, other means are used to attach thepolishing pad 340 to the pad support disk 343. Should it becomenecessary to replace the polishing pad 340, the polishing pad and thepad support disk 343 may be removed as a unit and replaced with a newplanarizing medium 348.

[0038] In one embodiment, the entire planarizing medium 348 may bedisposable. In another embodiment, the support disk 343 may be recycledby removing the old polishing pad 340 from the support disk andattaching a new polishing pad in its place. In either case, it may beadvantageous to adhesively attach the polishing pad 340 to the padsupport disk 343 rather than to adhesively attach the polishing pad tothe platen 320 directly (as may be done conventionally) because the padsupport disk 343 may be less costly than the platen. Accordingly, alarge number of low-cost pad support disks 343 with polishing pads 340attached may be kept on hand and available when needed. A furtheradvantage is that the pad support disk 343 may be attached to a porouspolishing pad 340, so that even the porous polishing pad may bereleasably attached to the platen 320 by applying a vacuum to thesupport disk 343.

[0039] As shown in FIG. 5A, the platen 320 may include a locking deviceor stop 334 in addition to the lip 321, to further resist relativelateral and/or vertical motion between the planarizing medium 348 andthe platen 320. In one embodiment, the stop 334 includes a female thread329 in the lip 321 that engages a corresponding male thread 345 in thepad support disk 343. In another embodiment, where the polishing pad 340is sufficiently rigid, the male thread 345 may be positioned in thepolishing pad 340, rather than in the support disk 343. Obviously, thepositions of the male thread 345 and the female thread 329 may beinterchanged without departing from the scope of the invention. In oneaspect of the embodiment shown in FIG. 5A, the threads 345 and 329loosely engage each other so as not to inhibit the action of the vacuumsource 370 as it draws the pad assembly 348 against the platen 320. Inanother embodiment, the threads 345 and 329 can more tightly engage eachother to still further resist relative motion between the planarizingmedium 348 and the platen 320. In one aspect of this embodiment, themechanical connection between the planarizing medium 348 and the platen320 can be secure enough to eliminate the need for the vacuum source 370and the vacuum passageway 323. An advantage of the stop 334 shown inFIG. 5A is that it may further decrease the likelihood that thepolishing pad 340 will separate from the platen 320, either axially orlaterally, if the vacuum source 370 is halted while the platen 320 ismoving.

[0040]FIG. 5B is a partial cross-sectional elevation view of a supportjig 350 for supporting the polishing pad 340 and the support disk 343during conditioning of the polishing pad 340. In one embodiment, thesupport jig 350 can include a vacuum passageway 323 a coupled to avacuum source 170 (FIG. 2) and/or a female thread 329 a that engages thecorresponding male thread 345 of the support disk 343. When the supportjig 350 includes the vacuum passageway 323 a to draw the support disk343 toward the support jig 350, the support disk 343 can include anon-porous attachment surface 347. When the support jig 350 includes thefemale thread 329 a to engage the support disk 343, the support disk 343and male thread 345 can include a relatively rigid material, such asmetal or hard plastic to engage the female thread 329 a. In otherembodiments, the support jig 350 can include any means for firmlysupporting the polishing pad 340 and the support disk 343. For example,in one embodiment, the support jig 350 can include a planarizingmachine, and in a specific aspect of this embodiment, a planarizingmachine that is no longer suitable for planarization.

[0041] The support jig 350 can include a pad conditioner 360 forconditioning the polishing pad 340. In one embodiment, the padconditioner 360 can include an end effector 361 coupled to a drivedevice 362 that moves the end effector in one or more directionsrelative to the polishing pad 340. In one aspect of this embodiment, theend effector 361 can have a diamond abrasive surface. Alternatively, theend effector 361 can include any surface or other means for removingmaterial from the planarizing surface or otherwise conditioning theplanarizing surface of the polishing pad 340.

[0042] An advantage of the support jig 350 and the pad conditioner 360shown in FIG. 5B is that they allow the pad 340 to be conditionedwithout requiring a planarization machine. Accordingly, the polishingpad 340 can be conditioned at the same time the planarization machine(with a different polishing pad installed) is used to planarizemicroelectronic substrates. For example, a new polishing pad 340typically requires conditioning during an initial “break-in” period toremove extraneous materials that may have been deposited on thepolishing pad 340 during manufacture or shipment. The support jig 350allows the break-in period to be completed without impacting thethroughput of planarization machines such as the one shown in FIG. 2.

[0043]FIG. 6 is a partial cross-sectional side elevation view of aplaten 420 having two stops 434 (shown as 434 a and 434 b) in accordancewith another embodiment of the invention. Each stop 434 may have ahandle 435 that projects from an aperture in the lip 421, and a tab 436toward the lower end of the handle 435. The tab 436 is sized and shapedto be received in a corresponding tab aperture 449 in the polishing pad440. The stop 434 may be placed in an engaged position (as shown by theone stop 434 a) by rotating the handle 435 until the tab 436 is withinthe corresponding tab aperture 449. The tab 436 may fit loosely withinthe tab aperture 449 to permit the vacuum source 470 to draw theplanarizing medium 448 toward the platen 420, substantially as wasdiscussed above with reference to FIG. 5. The stop 434 may be placed ina disengaged position (as shown by the other stop 434 b) by rotating thehandle 435 until the tab 436 is disengaged from the corresponding tabaperture 449, allowing the polishing pad 440 to be lifted from theplaten 420.

[0044] As is also shown in FIG. 6, the vacuum source 470 may bepositioned opposite the power supply 471 to balance the platen 420 whenthe platen rotates. In other embodiments, the power supply 471 may bepositioned at other circumferential locations relative to the vacuumsource 470, depending on the relative weights of the power supply andthe vacuum source. In still other embodiments, other functionalcomponents of the platen 420 may be used in place of, or in addition tothe power source 471 to balance the platen 420. An advantage of thisarrangement is that it eliminates the need for the counterweight 372(FIG. 5).

[0045]FIG. 7A is a partial cross-sectional side elevation view of aplaten 320 a having a conductive plate 390 that draws the support disk343 (with the polishing pad 340 attached) toward the platen uppersurface 330 via electrostatic forces. As shown in FIG. 7A, theconductive plate 390 can be used in place of the vacuum systemsdiscussed above with reference to FIGS. 2-6. In other embodiments, theconductive plate 390 can supplement a vacuum system such as one of thesystems shown in FIGS. 2-6.

[0046] The conductive plate 390 can include any conductive material,such as aluminum or copper and can be charged by applying an electricalvoltage to an electrode 391, which is electrically coupled to theconductive plate 390. The voltage on the conductive plate 390 canelectrostatically attract the support disk 343, causing the support disk343 to attach to the platen 320 a. Any charge induced by the voltage canlater be removed from the conductive plate 390 to detach the polishingpad 340.

[0047] In the embodiment shown in FIG. 7A, the support disk 343 caninclude the locking device 334 to further resist lateral and/or verticalmotion between the polishing pad 340 and the platen 320 a. In otherembodiments, the locking device 334 can be eliminated. An advantage ofthe platen 320 a shown in FIG. 7A is that it may be simpler to draw thepolishing pad 340 and the support disk 343 toward the platen 320 a withan electrostatic force than with other devices.

[0048]FIG. 7B is a partial cross-sectional view of a platen 320 b withthe conductive plate 390, and a polishing pad 340 a having particles 341distributed therein. The particles 341 can include a conductive materialor any material capable of receiving an attractive force from theconductive plate 390 in a manner generally similar to that discussedabove with reference to FIG. 7A. The particles 341 can also include aferrous material so as to draw the polishing pad 340 a toward the platen320 b via electromagnetic forces. Accordingly, the conductive plate 390can include a pair of electrodes 391 for passing a current through theconductive plate 390. The particles 341 can be distributed in agenerally uniform fashion, as shown in FIG. 7B, or the particles 341 canbe concentrated near the attachment surface 347 of the polishing pad 340a to increase the effect of the force between the polishing pad 340 aand the platen 320 a.

[0049]FIG. 8 is a partial cross-sectional side elevation view of a CMPapparatus 510 having a planarizing medium 548 that translates relativeto a fixed platen or base 520. The base 520 is supported by a supporttable 514 and generally includes a substantially incompressible materialto provide a flat, solid surface to which the planarizing medium 548 maybe secured during planarization. The CMP apparatus 510 further includesa positioning device 590 that draws the planarizing medium 548 over thebase 520. In the embodiment shown in FIG. 7, the positioning device 590includes a supply roller 591, first and second idler rollers 592 a and592 b, first and second guide rollers 594 a and 594 b, and a take-uproller 593. The supply roller 591 carries an unused part of theplanarizing medium 548, and the take-up roller 593 carries a used partof the planarizing medium 548. The supply roller 591 and/or the take-uproller 593 may be driven to sequentially advance unused portions of theplanarizing medium 548 onto the base 520. As such, unused portions ofthe planarizing medium 548 may be quickly substituted for worn or usedportions to provide a consistent surface for planarizing the substrate112. In one embodiment, the first idler roller 592 a and the first guideroller 594 a position the planarizing medium 548 slightly below the base520 so that the supply and take-up rollers 591 and 593 stretch theplanarizing medium 548 across the base during planarization. In otherembodiments, the planarizing medium 548 need not be stretched, as isdiscussed in greater detail below.

[0050] The base 520 includes a plurality of vacuum apertures 522 influid communication with a vacuum passageway 523. The vacuum apertures522 may have a circular cross-sectional shape, as shown in FIG. 7, ormay comprise slots or have other shapes in other embodiments. The vacuumpassageway 523 is connected to a conduit 528 that is in turn coupled tothe vacuum source 570, generally as was discussed above with referenceto FIG. 2. In the embodiment shown in FIG. 7, a liquid trap 524 may bepositioned in the conduit 528 and apart from the base 520 to separateliquid from the fluid drawn by the vacuum source 570. In anotherembodiment, the liquid trap 524 may form an integral component of thevacuum source 570.

[0051] In operation, the planarizing medium 548 is rolled up on thesupply roller 591 and one end is stretched over the base 520 andattached to the take-up roller 593. The vacuum source 570 is activatedto draw the planarizing medium 548 tightly against the base 520. Acarrier assembly 560 is moved relative to the planarizing medium 548 toplanarize the semiconductor substrate 112. Periodically, either duringthe planarization of a single semiconductor substrate 112, or after asemiconductor substrate has been planarized, the carrier assembly 560may be halted, the vacuum source 570 deactivated, and the planarizingmedium advanced slightly over the base 520 by rotating the take-uproller 593 and the supply roller 591. Once the planarizing medium 548has been advanced by a selected amount, the vacuum source 570 may bereactivated, and planarizing may recommence.

[0052] In an alternative embodiment (not shown), the vacuum source 570can be replaced with a voltage source to attract the planarizing mediumtoward the base 520 via electrostatic forces, in a manner generallysimilar to that discussed above with reference to FIGS. 7A-7B. In stilla further alternative embodiment, the base 520 can include a permanentmagnet or an electromagnet, as was discussed above with reference toFIG. 7B. It may be preferable to include an electromagnet rather than apermanent magnet to allow the magnet to be deactivated for advancing theplanarizing medium 548 across the base 520. In either alternativeembodiment, the planarizing medium 548 can include a conductive layeradjacent the base 520 in a manner generally similar to that shown inFIG. 7A. Alternatively, the planarizing medium 548 can include particlescapable of receiving an induced electrostatic or electromagnetic forcein a manner generally similar to that shown in FIG. 7B.

[0053] An advantage of the CMP apparatus 510 shown in FIG. 7 is that thesuction force, electrostatic force or electromagnetic force may moresecurely engage the planarizing medium 548 with the platen 520 and mayaccordingly prevent the planarizing medium from wrinkling or foldingwhen the semiconductor substrate 112 is planarized. A further advantageof the CMP apparatus 510 shown in FIG. 7 is that the planarizing medium548 may be releasably attached to the platen 520 without the need fortensioning the planarizing medium. Accordingly, the planarizing medium548 may be less likely to stretch or otherwise deform. Alternatively,the planarizing medium 548 may comprise a thinner, less costly sheetthan is conventionally used because it does not need to withstand hightension forces.

[0054] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. An apparatus for planarizing a semiconductor substrate, comprising aplaten having a generally flat engaging surface to at least partiallysealably engage a planarizing medium, the engaging surface having atleast one vacuum aperture sized and shaped to be coupled to a vacuumsource, the planarizing medium being drawn against the engaging surfaceof the platen when the vacuum source applies a vacuum to the vacuumaperture.
 2. The apparatus of claim 1, further comprising a carrierproximate to the platen, one of the carrier and the platen being movablerelative to the other of the carrier and the platen to remove materialfrom the semiconductor substrate when the semiconductor substrate ispositioned therebetween.
 3. The apparatus of claim 1, further comprisingthe planarizing medium, the planarizing medium including a polishing padhaving a generally nonporous surface that forms an at least partiallygas-tight seal with the engaging surface of the platen when the vacuumsource draws the planarizing medium against the platen.
 4. The apparatusof claim 3 wherein the polishing pad comprises polyurethane.
 5. Theapparatus of claim 3 wherein the polishing pad comprises glass.
 6. Theapparatus of claim 1, further comprising the planarizing medium, theplanarizing medium including a polishing pad and a pad support, the padsupport having first and second surfaces, the first surface of the padsupport being attached to the polishing pad, the second surface of thepad support being generally non-porous to form an at least partiallygas-tight seal with the engaging surface of the platen.
 7. The apparatusof claim 1 wherein the planarizing medium is elongated between a firstend and a second end, further comprising a supply device coupleable tothe first end of the planarizing medium and a take-up device coupleableto the second end of the planarizing medium to draw the planarizingmedium from the supply device across the platen.
 8. The apparatus ofclaim 7 wherein the supply device includes a first roller and thetake-up device includes a second roller, at least one of the first andsecond rollers being rotatable relative to the platen to draw theplanarizing medium across the platen.
 9. The apparatus of claim 1,further comprising a liquid trap in fluid communication with the vacuumsource and the vacuum aperture and positioned between the vacuum sourceand the vacuum aperture to at least restrict motion of liquid betweenthe platen and the vacuum source.
 10. The apparatus of claim 9 whereinthe liquid trap includes a passageway connected between the vacuumaperture and the vacuum source, the passageway having at least one bendto collect liquid from fluid drawn through the vacuum aperture.
 11. Theapparatus of claim 1 wherein the vacuum aperture is one of a pluralityof vacuum apertures in the engaging surface of the platen.
 12. Theapparatus of claim 1 wherein the vacuum aperture has a generallycircular cross-sectional shape.
 13. The apparatus of claim 1 wherein thevacuum aperture is elongated.
 14. The apparatus of claim 1 wherein theplanarizing medium has a first surface, a second surface opposite thefirst surface, and an intermediate surface between the first and secondsurfaces and the platen has a rim projecting from the engaging surface,the rim being adjacent to the intermediate surface of the planarizingmedium to restrict lateral movement of the planarizing medium relativeto the platen.
 15. The apparatus of claim 1, further comprising a stopconnected to the platen and releasably engageable with the planarizingmedium to restrict lateral motion of the planarizing medium relative tothe platen.
 16. The apparatus of claim 1 wherein the vacuum source ismounted to the platen.
 17. The apparatus of claim 16 wherein the platenhas a generally circular planform shape and the vacuum source is mountedtoward an edge of the platen, further comprising a counterweight mountedtoward the edge of the platen opposite the vacuum source.
 18. Theapparatus of claim 1 wherein the vacuum source is spaced apart fromplaten.
 19. The apparatus of claim 1 wherein the engaging surface of theplaten is positioned beneath the planarizing medium when the engagingsurface at least partially sealably engages the planarizing medium. 20.An apparatus for planarizing a semiconductor substrate, comprising: asupport; a platen coupled to the support and having a generally flatengaging surface to at least partially, sealably engage a planarizingmedium; and vacuum means in fluid communication with the platen fordrawing the planarizing medium against the engaging surface of theplaten.
 21. The apparatus of claim 20 wherein the vacuum means includesa vacuum aperture in a surface of the platen and a vacuum source coupledto the vacuum aperture to draw gas toward the vacuum source and draw theplanarizing medium against the platen.
 22. The apparatus of claim 20wherein the vacuum means includes a vacuum pump mounted to the platenand a power supply mounted to the platen and connected to the vacuumpump to power the vacuum pump when the platen moves relative to thesupport.
 23. The apparatus of claim 22 wherein the power supply includesa battery.
 24. The apparatus of claim 20 wherein the vacuum meansincludes a vacuum aperture in the engaging surface of the platen, avacuum source spaced apart from the platen, and a conduit connectedbetween the vacuum aperture and the vacuum source.
 25. The apparatus ofclaim 24 wherein the platen is movable relative to the support and theconduit includes a first portion coupled to the platen and a secondportion coupled to the vacuum source and sealed to the first portion,the first and second portions of the conduit being movable relative toeach other to allow the platen to move relative to the support while anat least partially gas-tight seal is maintained between the first andsecond portions of the conduit.
 26. The apparatus of claim 20 whereinthe engaging surface of the platen is positioned beneath the planarizingmedium when the engaging surface at least partially sealably engages theplanarizing medium.
 27. An apparatus for planarizing a semiconductorsubstrate, comprising: a support; a generally circular platen coupled tothe support, the platen having an engaging surface to at leastpartially, sealably engage a planarizing medium, the engaging surfacehaving a plurality of vacuum apertures, the platen further having a stopreleasably coupleable to the planarizing medium to at least restrictmotion of the planarizing medium relative to the platen; a vacuum sourceattached to the platen and coupled to the plurality of vacuum aperturesto draw the planarizing medium against the engaging surface of theplaten; and a power supply attached to the platen and coupled to thevacuum source to supply power to the vacuum source while the platenmoves relative to the support.
 28. The apparatus of claim 27 wherein thepower supply is attached to the platen at a circumferential positionselected to balance the platen when the platen rotates relative to thesupport.
 29. The apparatus of claim 27, further comprising a liquid trapconnected between the vacuum source and the vacuum aperture to at leastrestrict motion of liquid between the platen and the vacuum source. 30.The apparatus of claim 27 wherein the liquid trap includes a passagewayconnected between the vacuum apertures and the vacuum source, thepassageway having at least one bend to collect liquid from fluid drawnthrough the vacuum apertures.
 31. The apparatus of claim 27 wherein atleast one of the vacuum apertures includes an arcuate opening in theengaging surface of the platen.
 32. The apparatus of claim 27 whereinthe planarizing medium has a first threaded portion, the stop includes asecond threaded portion of the platen, the second threaded portion beingsized and shaped to releasably engage the first threaded portion of theplanarizing medium and restrict lateral and vertical motion of theplanarizing medium relative to the platen.
 33. The apparatus of claim 27wherein the planarizing medium has an aperture and the platen has a tabmember, the tab member being sized and shaped to be removably receivedin the aperture and restrict lateral and vertical motion of theplanarizing medium relative to the platen.
 34. The apparatus of claim 27wherein the planarizing medium has an upper surface and a lower surfaceopposite the upper surface, and the engaging surface of the platen atleast partially sealably engages the lower surface of the planarizingmedium.
 35. An apparatus for planarizing a semiconductor substrate,comprising: a platen having a generally flat engaging surface to engagean elongated planarizing medium, the engaging surface having at leastone vacuum aperture; a positioning device proximate to the platen andcoupleable to the planarizing medium to move the planarizing mediumacross the engaging surface of the platen; and a vacuum source coupledto the vacuum aperture to draw the planarizing medium against theengaging surface of the platen.
 36. The apparatus of claim 35, furthercomprising the planarizing medium, the planarizing medium having agenerally non-porous surface to form an at least partially gas-tightseal with the engaging surface of the platen when the vacuum sourcedraws the planarizing medium against the platen.
 37. The apparatus ofclaim 35, further comprising a carrier proximate to the platen to removematerial from the semiconductor substrate when the substrate ispositioned between the carrier and the platen and one of the carrier andthe platen is moved relative to the other of the carrier and the platen.38. The apparatus of claim 35 wherein the pad positioning deviceincludes a first roller connected to one end of the planarizing mediumand a second roller connected to an opposite end of the planarizingmedium, at least one of the first and second rollers being rotatablerelative to the platen to move the planarizing medium across the platen.39. The apparatus of claim 35, further comprising a liquid trapconnected between the vacuum source and the vacuum aperture to at leastrestrict motion of liquid between the platen and the vacuum source. 40.The apparatus of claim 35 wherein the liquid trap includes a channelconnected between the vacuum aperture and the vacuum source, the channelhaving at least one bend to collect liquid from fluid drawn through thevacuum aperture.
 41. The apparatus of claim 35 wherein the vacuum sourceis spaced apart from platen.
 42. The apparatus of claim 35 wherein theplanarizing medium has an upper surface and a lower surface opposite theupper surface, and the engaging surface of the platen at least partiallysealably engages the lower surface of the planarizing medium.
 43. Anapparatus for planarizing a semiconductor substrate, comprising a platenhaving a generally flat engaging surface to engage a planarizing medium,the platen including a conductive element coupleable to a signal sourceto produce an attractive force between the planarizing medium and theplaten to draw the planarizing medium toward the platen.
 44. Theapparatus of claim 43 wherein the conductive element is a firstconductive element, further comprising the planarizing medium, theplanarizing medium having a second conductive element.
 45. The apparatusof claim 44 wherein the planarizing medium includes a polishing padhaving a first surface facing toward the platen and a second surfaceopposite the first surface, the second conductive element including aconductive plate adjacent the first surface.
 46. The apparatus of claim44 wherein the planarizing medium includes a polishing pad having afirst surface and a second surface opposite the first surface, thesecond conductive element including a conductive particle between thefirst and second surfaces.
 47. The apparatus of claim 44 wherein thesecond conductive element includes a ferrous material.
 48. The apparatusof claim 44 wherein the second conductive element is adhesively bondedto the planarizing medium.
 49. The apparatus of claim 43 wherein theconductive element is coupled to a voltage source.
 50. The apparatus ofclaim 43 wherein the conductive element includes a permanent magnet. 51.The apparatus of claim 43 wherein the conductive element includes anelectromagnet.
 52. A planarizing medium for a planarizing machine,comprising: a polishing pad having a planarizing surface and a supportsurface opposite the planarizing surface; and a pad support having firstand second opposite surfaces, the first surface being attached to thesupport surface of the polishing pad, the pad support being releasablyattached to the planarizing machine.
 53. The planarizing medium of claim52 wherein the polishing pad includes a generally flexible material andthe pad support includes a generally rigid material.
 54. The planarizingmedium of claim 52 wherein the second surface of the pad support isgenerally non-porous.
 55. The planarizing medium of claim 52 wherein thepad support includes a first thread to engage a second thread of theplanarizing machine and secure the pad support to the planarizingmachine.
 56. The planarizing medium of claim 52 wherein the polishingpad is removably attached to the pad support.
 57. A method for removablyattaching a planarizing medium to a platen of a planarizing machine,comprising: positioning the planarizing medium adjacent the platen; andapplying a vacuum to an attachment surface of the planarizing medium todraw the planarizing medium against the platen.
 58. The method of claim57, further comprising forming an at least partially gas-tight sealbetween the planarizing medium and the platen.
 59. The method of claim57 wherein the planarizing medium includes a polishing pad having firstand second surfaces and a pad support having first and second surfaces,the attachment surface of the planarizing medium comprising the secondsurface of the pad support, the method further comprising attaching thefirst surface of the polishing pad to the first surface of the padsupport.
 60. The method of claim 59 wherein the act of attaching thefirst surface of the polishing pad to the first surface of the padsupport includes positioning an adhesive between the first surface ofthe polishing pad and the first surface of the pad support.
 61. Themethod of claim 57 wherein the act of applying a vacuum to theplanarizing medium includes drawing a fluid through at least one vacuumaperture in a portion of the platen adjacent the pad assembly.
 62. Themethod of claim 61 wherein the fluid includes a liquid and a gas,further comprising removing the liquid from the fluid.
 63. The method ofclaim 57 wherein the planarizing medium has a planarizing surfaceopposite the attachment surface and an intermediate surface between theplanarizing surface and the attachment surface, the method furthercomprising engaging the intermediate surface of the planarizing mediumto at least restrict lateral movement of the planarizing medium relativeto the platen.
 64. The method of claim 57, further comprising engaging areleasable stop with the planarizing medium to releasably secure theplanarizing medium to the platen.
 65. The method of claim 60 wherein thestop includes a tab member attached to one of the planarizing medium andthe platen, a tab aperture in the other of the planarizing medium andthe platen, and the act of engaging the stop includes inserting the tabmember into the tab aperture.
 66. The method of claim 64 wherein thestop includes a first threaded portion of the planarizing medium and acorresponding second threaded portion of the platen and the act ofengaging the stop includes engaging the first threaded portion with thesecond threaded portion.
 67. The method of claim 57, further comprising:releasing the vacuum; moving the planarizing medium laterally relativeto the platen; and applying the vacuum to draw the planarizing mediumback against the platen.
 68. The method of claim 57, further comprising:attaching a vacuum source to the platen; and attaching a counterweightto the platen to balance the vacuum source.
 69. The method of claim 57wherein the act of attaching a counterweight includes attaching a powersupply to the platen, further comprising coupling the power supply tothe vacuum source.
 70. The method of claim 57 wherein the attachmentsurface of the planarizing medium is a lower surface and the act ofapplying a vacuum includes applying a vacuum to the lower surface of theplanarizing medium to draw the lower surface of the planarizing mediumagainst an upper surface of the platen.
 71. A method for planarizing asemiconductor substrate with a planarizing machine, the planarizingmachine having a platen, a first planarizing medium, and a carrier toengage the semiconductor substrate with the first-planarizing medium,the method comprising: positioning the first planarizing medium adjacentthe platen; applying a vacuum to a plurality of apertures in a surfaceof the platen to form an at least partially gas-tight seal between thefirst planarizing medium and the platen; moving at least one of theplaten and the carrier relative to the other of the platen and thecarrier to remove material from the semiconductor substrate; releasingthe vacuum; and removing the first planarizing medium from the platenand positioning a second planarizing medium adjacent the platen.
 72. Themethod of claim 71 wherein the first planarizing medium includes apolishing pad having first and second surfaces and a pad support havingfirst and second surfaces, further comprising attaching the firstsurface of the polishing pad to the first surface of the pad supportwith an adhesive.
 73. The method of claim 71, further comprisingremoving liquid from a fluid drawn through the vacuum apertures.
 74. Themethod of claim 71 wherein the planarizing medium has an attachmentsurface adjacent the platen, a planarizing surface opposite theattachment surface, and an intermediate surface between the planarizingsurface and the attachment surface, the method further comprisingengaging the intermediate surface of the planarizing medium with theplaten to at least restrict lateral movement of the planarizing mediumrelative to the platen.
 75. The method of claim 71 wherein theintermediate surface has a first threaded portion and the platen has asecond threaded portion, and the act of engaging the intermediatesurface includes threadably engaging the first threaded portion with thesecond threaded portion.
 76. The method of claim 71 wherein the act ofapplying a vacuum includes applying a vacuum to a lower surface of theplanarizing medium to form an at least partially gas-tight seal betweenthe lower surface of the planarizing medium and an upper surface of theplaten.
 77. A method for releasably attaching a planarizing medium to aplaten of a planarizing machine, the planarizing machine having carrierthat engages a surface of a semiconductor substrate with a surface ofthe planarizing medium, the planarizing machine further having apositioning device connected to opposite ends of the planarizing mediumto move the planarizing medium across the platen, the method comprising:positioning the planarizing medium adjacent the platen; and resistinglateral motion of a portion of the planarizing medium relative to theplaten by applying a vacuum to the portion of the planarizing medium,the portion of the planarizing medium being laterally spaced apart fromthe carrier when the carrier engages the semiconductor substrate withthe planarizing medium.
 78. The method of claim 77, further comprisingforming an at least partially gas-tight seal between the planarizingmedium and the platen.
 79. The method of claim 77, further comprising:releasing the vacuum; moving the planarizing medium laterally relativeto the platen; and re-applying the vacuum to draw the planarizing mediumback against the platen.
 80. The method of claim 77 wherein the act ofapplying a vacuum to the planarizing medium includes drawing fluidthrough at least one vacuum aperture in a portion of the platen adjacentthe planarizing medium.
 81. The method of claim 80 wherein the fluidincludes a gas and a liquid, further comprising removing liquid from thefluid.
 82. The method of claim 77 wherein the positioning deviceincludes a supply device connected to a first end of the planarizingmedium and a take-up device connected to a second end of the planarizingmedium opposite the first end of the planarizing medium, furthercomprising activating at least one of the supply device and the take-updevice to move the planarizing medium laterally across the platen. 83.The method of claim 77 wherein the planarizing medium is elongatedbetween a first end and a second end and the pad positioning deviceincludes a supply roller attached to the first end of the planarizingmedium and a take-up roller attached to the second end of theplanarizing medium, the method further comprising rotating the take-uproller to draw the planarizing medium from the supply roller across theplaten.
 84. The method of claim 83, further comprising rotating thesupply roller.
 85. The method of claim 77 wherein the portion of theplanarizing medium includes a lower surface of the planarizing mediumand the act of resisting lateral motion of the portion includes drawingthe lower surface of the planarizing medium against an upper surface ofthe platen.
 86. A method for planarizing a semiconductor substrate witha planarizing machine, the planarizing machine having a platen, a firstplanarizing medium adjacent the platen, and a carrier movable relativeto the platen, the method comprising: applying a vacuum to a pluralityof apertures in a surface of the platen to form an at least partiallygas-tight seal between the first planarizing medium and the platen;moving at least one of the platen and the carrier relative to the otherof the platen and the carrier to remove material from the semiconductorsubstrate; releasing the vacuum; and replacing the first planarizingmedium with a second planarizing medium.
 87. The method of claim 86wherein the planarizing machine includes a stop to releasably lock theplanarizing medium to the platen, further comprising releasing the stopbefore removing the first planarizing medium from the platen.
 88. Themethod of claim 86, further comprising removing liquid from a fluiddrawn through the vacuum apertures.
 89. A method for removably attachinga planarizing medium to a platen of a planarizing machine, comprisingapplying a signal to the platen that produces an attractive forcebetween the platen and the planarizing medium.
 90. The method of claim89, further comprising positioning the platen adjacent to theplanarizing medium.
 91. The method of claim 89 wherein applying thesignal includes passing an electrical current through the platen andattracting the planarizing medium via an electromagnetic force.
 92. Themethod of claim 89 wherein the planarizing medium includes a polishingpad and a support member and applying a signal includes applying asignal that produces an attractive force between the platen and thesupport member.
 93. The method of claim 89 wherein the planarizingmedium includes a polishing pad having conductive particles and applyinga signal includes applying a signal that produces an attractive forcebetween the platen and the conductive particles.
 94. The method of claim89 wherein applying a signal includes applying a voltage to the platenthat causes an electrostatic attraction between the platen and theplanarizing medium.
 95. A method for conditioning a polishing pad of aplanarizing machine, comprising: attaching the polishing pad to agenerally rigid pad support; releasably supporting the pad support toposition the polishing pad adjacent an end effector; and engaging aplanarizing surface of the polishing pad with the end effector tocondition the polishing pad.
 96. The method of claim 95 whereinattaching the polishing pad includes releasably attaching the polishingpad.
 97. The method of claim 95 wherein supporting the pad support andthe polishing pad includes applying a vacuum to the pad support.
 98. Themethod of claim 95 wherein supporting the pad support and the polishingpad includes engaging a threaded portion of the pad support with acorresponding threaded portion of a support jig.